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Dental Chair Redesigned for "Low-Resource Settings"

Dental Faculty, Students Help Engineering Students

Ann Arbor, MI — January 14, 2015 — A vital piece of equipment used in dental offices worldwide has been redesigned by a team of students from the U-M College of Engineering with help from faculty and students at the U-M School of Dentistry.

The idea for the revamped chair was inspired by a maxillofacial surgeon from Ghana who noticed in his travels to many local villages that conventional dental chairs were expensive, complex to use, and could be operated only when the local power supply was on. Dentists lacking funds and who practiced in areas where electricity was not reliable instead often used plastic lawn chairs, wooden kitchen chairs, tables or even school desk chairs to seat patients and provide care to them.

The dental surgeon approached U-M for help in designing a piece of equipment dentists could use to change that. What emerged was a “multi-purpose dental chair for low-resource settings” that was developed by a group of mechanical engineering students who approached School of Dentistry faculty and students for help.

Important Criteria

A member of the engineering group, Christopher Easterday, said the focus of the student-led initiative was to design and manufacture a prototype that would be inexpensive, easy to operate, simple to maintain and not require the use of electricity.

“The surgeon in Ghana reached out to the University of Michigan for help with designing a piece of equipment that was more suitable to the settings where it would be used,” Easterday said. He and three other engineering students, Michelle Howard, Alexander Bauman and Adrian Kane, embraced the challenge.

“We thought this was a very interesting project because it was different,” Easterday said. “We weren’t just trying to improve an existing product. We wanted to design a new piece of equipment that was affordable and could be used in an environment where infrastructure was often unreliable.”

Help from the School of Dentistry

Easterday and his group contacted Dr. Yvonne Kapila for her help. Kapila, a professor in the Department of Periodontics and Oral Medicine, is also director of the School’s Global Oral Health Initiative. For the past four years, she has taken groups of students to Kenya to provide oral health care in remote villages.

“Based on our experiences in Kenya, and from what many of our dental students have experienced providing oral health care in other parts of the world, we had a pretty good idea what the engineering students wanted to achieve in terms of functionality and price,” Kapila said. The dental chair used in most dental offices in the Western world typically costs about $20,000 and offers a wide range of electronic features that enable a dentist to easily adjust and position a patient when providing care.

Easterday appreciated the help he and his group received. “Most of the inspiration we received came when Dr. Kapila showed us some of the dental chairs in the School of Dentistry’s Sindecuse Museum,” he said. “Those early dental chairs more closely resembled what we were looking for in designing our chair for a different environment.”

Three months elapsed from the time they began working on a conceptual design for the chair until it was unveiled in December at a College of Engineering Design Expo.

The redesigned chair met important criteria set by Easterday and his group.

In the video, engineering students Christopher Easterday and Alexander Bauman demonstrate using the dental chair.

The cost of the prototype was approximately $1,600. It runs without electricity, features an adjustable backrest and leg rest, includes a foot pump for vertical adjustments, and can accommodate the height (4-1/2 feet to 6-1/2 feet) and weight (up to 450 pounds) of virtually all men and women in sub-Saharan Africa. The chair also includes an adjustable overhead light of low-power, battery-operated 10-watt light-emitting diodes (LEDs).

Dental Faculty and Student Insights

Kapila said some of the faculty and dental students provided important information to help the engineering students design the prototype.

“The barber-style foot pump was a key element in designing the chair, since that would eliminate the need for electricity to raise or lower the chair,” she said. “Also designing the chair so a patient could completely recline was another important element.”

Kapila added, “this design is a huge improvement over what is typically used now.” However, she recommended that future chairs be made of material could be easy to wipe down with chemical agents such as diluted bleach. She also recommended the head rest have a tapered configuration to allow for easier access by a dentist.

Easterday said the biggest challenge his group faced was manufacturing the prototype. He said the chair needed many custom machined steel parts and “a lot of welding was also needed.” Another problem the group encountered was designing an adequate locking mechanism to keep the backrest locked in position.

When the prototype was unveiled during the College of Engineering’s Design Expo in early December, it received favorable reviews.

“I am thrilled with the initiative demonstrated by the engineering students and their collaboration with the faculty and students here at the School of Dentistry,” Kapila said. “Working separately, neither group would have been able to develop this prototype. Working together, however, both dentists and engineers were able to develop a product that one day may become commonplace in health facilities and dental offices not just in Africa, but other parts of the world as well. We may even be able to test it during our next visit to Kenya.”

Another group of students will be refining the design of the current prototype with an eye on mass production of the dental chair. “Since this is a first-round prototype, hopefully another class will pick up where we have left off to make mass production possible. However, that may be a semester or two away,” Easterday said.

Easterday said the biggest lesson his group learned “was that, as an engineer, one needs to be flexible and willing to make changes to a design when you receive new information.” He said that after finishing their first design of the dental chair, they presented it to the oral and maxillofacial surgeon in Ghana who suggested ways to improve it. “We ended up changing the entire design of the dental chair based on his recommendations,” Easterday said.